The subject matter of the earlier patent application Ser. No. 857,030, filed Dec. 2, 1977 is a mechanically or electrically operated toothbrush, incorporated in a housing, which is characterized in that situated at the rotation output end is an eccentrically mounted disk, wherein one or more funnel-shaped openings are eccentrically situated, serving as the end bearing for receiving a drive shaft whose outer support with ball head or of flexible material is situated in the toothbrush housing and whose end is formed directly as a holder for a push-in brush. By the arrangement of the drive of this toothbrush, it is possible to carry out a rotary to elliptical cleaning movement desired in dental medicine.
In this connection, however, there arises the necessity to vary the rotational direction of the cleaning movement, depending on the application of the brush to the dentition. This occurs according to a preferred design of the earlier patent application by the arrangement of a reversing switch by means of which the rotational direction of the rotating output disk may be varied.
Although such reversing switch per se provides for a satisfactory handling of the switching of the toothbrush according to the earlier patent, this solution may seem cumbersome to some users to the extent that they must undertake a switching after the cleaning of every tooth section on the inside and outside of the dentition. For the non-mechanically inclined user or for children, problems could result therefrom.
This also holds true with respect to a further preferred embodiment of the earlier patent application, according to which the reversing switch is formed in such a manner that it may be actuated by lip or pressure. This too, requires a certain dexterity of the user. Furthermore, the formation of such a switch is visually troublesome and upon utilization also annoying to the user.
Furthermore, known from DT-OS No. 2 363 364 is an electric toothbrush whose operation is initiated by the pressure of the toothbrush on the teeth. Entirely aside from the fact that this does not cause a "reversal" of the rotational direction of the brush, the actuation is not afforded by the variable pressure forces exerted by the user.